The response of rice varieties to Meloidogyne graminicola from the Mekong Delta, Vietnam

Abstract

Summary The rice root-knot nematode, Meloidogyne graminicola, is a serious pathogen of rice production worldwide. In Vietnam, scientific information on the rice root-knot nematode is limited. In this circumstance, our study aimed to investigate the characteristics of M. graminicola from rice fields in southern Vietnam and to evaluate the reaction of 20 rice varieties to this soil-borne pathogen in a glasshouse experiment. Ten populations of root-knot nematode collected from rice fields at different geographical regions in the Mekong Delta were identified as M. graminicola based on the perineal configuration of females and species-specific molecular markers. The morphological, morphometric and molecular characteristics of ten nematode isolates were defined, and the variations observed between these isolates were not significantly different. The pathogenicity of these isolates was examined in the susceptible Indica rice, Oryza sativa ‘IR64’, with a reproduction factor ranging from 18.1 to 37.8. Of the 20 Indica rice varieties tested in response to the nematode population MG-PN08, the ‘Tetep’ variety showed moderate resistance to the nematode (reproductive factor = 11.7; galling index = 2.4), while others were ranked at levels ranging from moderately susceptible to highly susceptible. The life cycle of M. graminicola in ‘Tetep’ root is 28 days compared to 21 in ‘IR64’. ‘Tetep’-nematode interaction at the histological and molecular levels needs further investigation to develop new rice varieties resistant to rice root-knot nematode.

Remembering a forgotten war: The Vietnamese state, war veterans and the commemoration of the Sino-Vietnamese War (1979–89)

“…Due to a change in tactics in May 1985, the Vietnamese troops managed to reoccupy Peak A6B, which was a turning point of the war in Vi ̣ Xuyên because the Vietnamese side had proven that it could hold its position against fierce Chinese counterattacks. 64 The PLA suffered heavy casualties in further clashes in September 1985 and from then on focused on holding its positions and making small-scale attacks. 65 The Chinese launched a broad attack for the last time in January 1987, but the PAVN had taken pre-emptive measures beforehand and managed to repel the assault.…”

“…This was because the military headquarters of Hà Giang province had not assigned the task of finding soldiers' remains to a specific unit of the army, but had delegated it to a non-military company that had mainly cleared landmines and unexploded shells there. 86 As a result of this negligence and lack of interest, the remains of approximately 2,000 soldiers who fell at Vị Xuyên are still unaccounted for. 87 Since the Vietnamese state had not paid due attention to finding and burying the fallen soldiers, many of their surviving comrades felt deeply obliged to fill the gap and consequently set about the task of finding fallen comrades themselves using their own limited resources.…”

“…95 Approximately 600 delegates representing the veterans of the Vị Xuyên battlefront held the first meeting of the Liaison Committee in Hanoi on 14 July 2016. 96 Major General Nguyê ˜n Đúc Huy acted as chairman of the Committee. In his inaugural address, he made various recommendations to the VCP and the Vietnamese state in the hope that they would do the following: 4.…”

“…The self-congratulatory tendency of the TV documentary is in line with the false claim that the VCP and the Vietnamese state had always commemorated the war against China and always taken care of the veterans and fallen soldiers. 110 In July 2019, the veterans of Vị Xuyên celebrated the 35th 'death anniversary' of the MB84 campaign. The same year witnessed celebrations for the 40th anniversary of the outbreak of the war against China in 1979 and the bloodiest battle against Chinese troops in Hà Giang in 1985.…”